The present invention relates to devices for injecting, dispensing, administering, infusing or delivering a substance, and to methods of making and using such devices. More particularly, it relates to a device for dispensing a substance, e.g. an injection device or an injection pen, which has a spring for administering a measured dose of an injectable product or substance from an ampoule, a double-chamber ampoule, for example. Some embodiments of such a device may be used for self-administering the product or substance. In some embodiments, the device may take the form of a disposable injection device or injector, in others, an automatic injection device or automatic injection pen.
U.S. Pat. No. 5,104,380 discloses an injection device wherein the injection needle is fitted on the device manually and the subsequent dispensing of an active substance from the device takes place automatically by a drive. The drive is provided in the form of a spring, which is tensioned by a movement of a dose setting element to set a desired dose to be administered. The spring is blocked or locked in the tensed state until activated. Upon activation, it automatically drives a dispensing mechanism, which drives or moves the active substance through the injection needle.